The present invention relates generally to pulse generation, and in particular to a pulse generator of the corona discharge type which is suitable for accurately sensing engine crankshaft angle. The invention is particularly suitable for ignition control systems in which predetermined ignition timing data is stored for use in later retrieval in response to a set of sensed engine speed and power.
Conventional methods of detecting crankshaft angle, or angular displacement of the crankshaft from a reference point, involves the use of electromagnetic or photoelectrical sensing elements mounted on a rotor for rotation with the crankshaft, a stator being provided to detect changes in magnetic flux or optical energy. However, the conventional methods are found to be unsatisfactory because of the difficulty in having as many such sensing elements provided on the restricted space of the rotor surface as desired to generate sufficient number of pulses for each crankshaft revolution to permit accurate measurement of its angular displacement. Accurate measurement of crankshaft angle is essential to the ignition system of internal combustion engines provided with exhaust gas recirculation in which ignition timing is related to the varying rate of recirculated exhaust gases as a function of engine power and speed.